Centrifugal countercurrent chromatography has been successful in high efficiency analytical separation with a variety of two-phase solvent systems. For example, see Y. Ito and R. L. Bowman, (1975) Anal. Biochem., 65,310; Y. Ito and R. L. Bowman, U.S. Pat. No. 3,856,669, Dec. 24, 1975; and Y. Ito and R. L. Bowman, U.S. Pat. No. 3,775,309, Nov. 27, 1973. In these systems, two immiscible or partially soluble liquid phases are brought into contact for the transfer of one or more components. In helix countercurrent chromatography, a horizontal helical tube is filled with one phase of a two-phase liquid and the other phase is introduced at one end of the helix and passes through to the first phase. In these systems, to enable the countercurrent process to take place inside a very small-diameter tube having a maximum number of turns, it is desirable to enhance the gravitational field by the use of centrifugation.
As reported, for example, in Y. Ito and R. L. Bowman, Science, 173, 420 (1971), a rotating helical column in an acceleration field has a capability of retaining the stationary phase as the mobile phase continuously elutes through the column. Consequently, solutes locally introduced are subjected to an efficient partition process and are separated according to their relative partition coefficients. The flow-through coil planet centrifuge technique in certain circumstances has yielded an efficiency up to 10,000 T.P. with a fine analytical column in a strong centrifugal force field, while in other circumstances efficient preparative scale separations have been successful with a slowly rotating helical column in the gravitational field. It would be desirable to have a system able to deal with a wide inclusive range of such circumstances, wherein the helical column array rotates with respect to both gravitational and centrifugal force fields.
Further background will be given by examining the following U.S. prior patents, which appear to represent the closest prior art relating to the present invention, found in the course of a preliminary search:
Ito et al, U.S. Pat. No. 3,775,309 PA1 Ito et al, U.S. Pat. No. 3,856,669 PA1 Ito, U.S. Pat. No. 3,994,805.